This invention relates generally to an automatic control system for a work machine. More particularly, the invention relates to an automatic system for orienting a swing axis of the work machine.
Excavating type machines, such as a backhoe loader, are versatile machines equipped with a work implement, such as a bucket mechanism, for grading slopes, digging trenches, and performing other excavations. These excavations are often in close proximity to buildings, sidewalks, or buried utilities.
On any ground or terrain, an operator must take care to properly orient the excavating type machine prior to beginning work or the machine will not dig with a clean horizontal surface. For instance, if the excavating type machine were leaning to one side on a flat surface, the bucket would dig in deeper at one corner of the bucket than the other. The ability to dig a vertical face or a ditch with a vertical wall is especially hindered by an out-of-level machine. An out-of-level machine can result in an out-of-level bucket that either digs a ditch with an angled face or creates a somewhat vertical face having jagged edges.
When an excavating type machine, such as a backhoe loader, is used to grade a slope, the backhoe is stationed in position at the top edge of the grade. The boom and bucket extend from the backhoe over the edge of the slope. An operator manipulates the bucket down onto the sloped ground to remove or distribute dirt along the slope. The boom and bucket are pivoted about a swing axis and extended to grade all accessible regions of the slope. During grading, the edge of the bucket maintains a proper roll position of being parallel to the plane of the graded slope only when the boom is pointing either directly down the slope or along the steepest gradient of the slope. If the boom pivots about the swing axis to any direction that is not directly down the slope or along the steepest gradient, the bucket edge will not be parallel to the slope face. As such, when grading or moving dirt, one edge of the bucket will dig in before the other edge, causing ridges in the dirt, instead of the desired flat surface.
Some excavating type machines are equipped with stabilizing arms configured to remove the weight of the machine from the machine tires and to stabilize the machine during the digging operation. These stabilizing arms are also used to level the machine. However, the leveling operation is typically only an approximation and is dependant on the judgment of the machine operator. If the operator""s judgment is not good, the excavation may be angled considerably, which may result in damage to adjacent structures or to previously buried cables or pipelines.
One attempt to address the deficiencies described above is disclosed in U.S. Pat. No. 5,288,196 to Sutton, II, issued Feb. 23, 1999. The ""196 patent discloses a computer controlled backhoe having a frame with an imaginary roll axis and a pitch axis. Two outriggers are used to level the frame relative to the roll axis with appropriate hydraulic actuators to move the outriggers. The system includes a dual axis gyro, which continuously senses the positions of the roll and pitch axes of the frame. The information is supplied to a computer, which compensates for changes in the frame position. The ""196 patent, however, does not provide an automated control system capable of continuously adjusting the swing axis of a work machine digging assembly to a desired orientation.
The present invention is directed to overcoming one or more of the problems or disadvantages associated with the prior art.
One aspect of the present invention is a control system for orienting a swing axis of a work machine. The work machine includes a swing frame and a frame structure, and the control system includes an operator interface configured to receive operator inputs, wherein the operator inputs represent a desired orientation of the swing axis of the swing frame. The control system also includes a sensor assembly configured to determine an actual orientation of the swing axis of the swing frame and a controller configured to compare the desired orientation to the actual orientation of the swing axis to determine a swing angle. The controller is adapted to output the swing angle.
In another aspect of the invention, a method of orienting a swing axis of a work machine having a swing frame and a frame structure is disclosed. The method includes the steps of entering operator inputs into an operator interface, wherein the operator inputs represent a desired orientation of the swing axis of the swing frame, sensing the actual orientation of the swing axis, comparing the desired orientation to the actual orientation of the swing axis to determine a swing angle, and adjusting the swing axis based on the swing angle to obtain the desired orientation of the swing axis.